A car bomb in a vegetable market in the northern Iraqi town of Tal Afar killed 18 people and injured 25 on Friday, police said. A US army spokesperson, Sam Smith, put the death toll at 20. The town is located near the city of Mosul.

Meanwhile, Shiite leader Moqtada Sadr has ordered his Mahdi Army militia to lay down its arms if a security accord between Baghdad and Washington provides for a withdrawal from Iraq, his spokesman said on Friday. "We want to see whether the provisions of the agreement are serious. We will be satisfied if the agreement contains the withdrawal of US forces," Salah al-Obeidi, chief spokesman for the Sadr movement, told AFP.

"If so, we will complete the reorganisation of the Mahdi Army which aims to transform it into a social organisation," he said. However, he also warned that if the withdrawal terms were not written into the agreement then Sadr's forces would remain armed. "We will be forced to await the decision of withdrawal of American forces."